Pump reversal causes an overload alarm on the inverter
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Hello, everyone! I have a water supply pump here, a horizontal centrifugal pump with the motor connected directly to it, and it features constant pressure control. Due to a damaged outlet check valve, the pump reverses direction when it stops running. When the pump is in automatic mode, an overload alarm on the frequency converter occurs frequently; this problem did not exist before. The electrician believes that the overload alarm is caused by the pump reversing direction. Has anyone else encountered this issue? I have seen the pump run in reverse before, and there was no overload when it was started directly. Could someone explain this? Not very grateful
This is because the torque during direct starting and variable-frequency starting is different, which causes the inverter to give an alarm
As the poster said, there’s a problem with the check valve at the outlet – it can’t be closed properly, which causes the pump to run in reverse due to backflow of the fluid!
In actual operation, if such problems do arise, it is recommended to change the approach: before shutting down the pump, close the outlet valve first, and then proceed with shutting down the pump, in order to prevent similar situations from occurring and causing damage to the pump, motor, and related components.
It would be best to recall the basic electrical concepts from middle school physics, specifically those related to generators and motors; this knowledge might help explain this phenomenon. For reference.